It is helpful to control melting temeprature to set time-alarm in melting system. It is effective to determine the switch point from slow injection to fast injection and to slect punch velocity of fast injection for ensuring ejection speed. It is beneficial to set overflow channel and cooling water channel for the balance of mould temeprature. Gas hole and inclusion can be reduced by properly increasing thickness,and quality of the chilling layer, uniformly spraying and cleaning the mould cavity on time. The mechanical properties of die casting parts can be improved by ageing at lower temeprature.